Semiconductor package and method of manufacturing same

1. A semiconductor package which electrically connects a semiconductor chip and a printed circuit board using a solder ball, the semiconductor package further comprising a thermal buffer layer which is positioned on a semiconductor chip, absorbs and disperse heat generated by the semiconductor chip, increases a distance between the semiconductor chip and a printed circuit board to decrease a deviation of a heat conduction process, and has a thickness ranging from 7.5 to 50% of a diameter of a solder ball, wherein the thermal buffer layer includes a resin coated film in contact with chip pad side surface of the semiconductor chip and a passivation layer formed on the resin coated film, wherein the passivation layer has a multilayer structure, wherein: a lowest layer of the multilayer structure is positioned on an entirety of the resin coated layer; and a highest layer of the multilayer structure is disposed on a part of the resin coated layer such that a step is formed on an under bump metallization on which the solder ball is seated.

2. The semiconductor package of claim 1 , wherein the thermal buffer layer has the thickness ranging from 15 to 100 μm.

3. The semiconductor package of claim 1 , wherein: the under bump metallization includes a lower region of the step, which is a region in contact with a re-distribution layer, an upper region of the step, which is positioned on the passivation layer, and a step surface, which connects the upper region and the lower region of the step; and a central portion of the solder ball is positioned on the lower region of the step and a peripheral portion of the solder ball is positioned on the upper region of the step.

4. The semiconductor package of claim 2 , wherein the thickness of the thermal buffer layer and a thickness of the semiconductor chip are adjusted such that an overall thickness of the semiconductor package is constant.

5. The semiconductor package of claim 1 , further comprising an epoxy molding compound which supports a side portion of the solder ball on the thermal buffer layer.

6. A method of manufacturing a semiconductor package, the method comprising: a) forming a resin coated film on a semiconductor chip and forming a re-distribution layer in contact with an electrode of the semiconductor chip on a part of an upper portion of the resin coated film; b) forming a passivation layer which is positioned on the resin coated film and is a thermal buffer layer, which exposes an upper central portion of the re-distribution layer, to have a thickness ranging from 7.5 to 50% of a diameter of a solder ball; c) forming an under bump metallization in contact with the re-distribution layer; and d) forming the solder ball which electrically connects the under bump metallization and a printed circuit board.

7. The method of claim 6 , wherein the passivation layer is formed as a plurality of layers, wherein: a lowest layer of the plurality of layers is formed on an entirety of the resin coated film; and a highest layer thereof is formed to be positioned under a peripheral portion of the under bump metallization.

8. The method of claim 6 , wherein: the under bump metallization includes a lower region of a step, which is a region in contact with the re-distribution layer, an upper region of the step, which is positioned on the passivation layer, and a step surface which connects the upper region and the lower region of the step; and a central portion of the solder ball is positioned on the lower region of the step and a peripheral portion of the solder ball is positioned on the upper region of the step.

9. The method of claim 6 , further comprising forming an epoxy molding compound, which supports a side portion of the solder ball, on the thermal buffer layer.

10. The method of claim 6 , wherein a thickness of the thermal buffer layer and a thickness of the semiconductor chip are adjusted such that an overall thickness of the semiconductor package is constant.

11. The method of claim 10 , wherein a rear surface of the semiconductor chip is ground by an amount by which the thickness of the thermal buffer layer is increased.

12. A method of manufacturing a semiconductor package comprising: a-1) forming a resin coated film, which is a thermal buffer layer, on a semiconductor chip to have a thickness ranging from 7.5 to 50% of a diameter of a solder ball and forming a re-distribution layer in contact with an electrode of the semiconductor chip on a part of an upper portion of the resin coated film; b-1) forming a passivation layer which is positioned on the resin coated film and is a thermal buffer layer which exposes an upper central portion of the re-distribution layer; c-1) forming an under bump metallization in contact with the re-distribution layer; and d-1) forming the solder ball which electrically connects the under bump metallization and a printed circuit board.

13. The method of claim 12 , wherein: the under bump metallization includes a lower region of a step, which is a region in contact with the re-distribution layer, an upper region of the step, which is positioned on the passivation layer, and a step surface which connects the upper region and the lower region of the step; and a central portion of the solder ball is positioned on the lower region of the step and a peripheral portion of the solder ball is positioned on the upper region of the step.

14. The method of claim 12 , further comprising forming an epoxy molding compound, which supports a side portion of the solder ball, on the thermal buffer layer.

15. The method of claim 12 , wherein a thickness of the thermal buffer layer and a thickness of the semiconductor chip are adjusted such that an overall thickness of the semiconductor package is constant.

16. The method of claim 15 , wherein a rear surface of the semiconductor chip is ground by an amount by which the thickness of the thermal buffer layer is increased.